Crack Cause Analysis And Preventive Measurses Of Spherical Tank

Spherical tank is widely used in petroleum, chemical industry, it is an important equipment in petrochemical plant. Compared with other shapes, spherical tank has the central symmetry of its geometry, so it has the uniform stress. Under the same condition of thickness, the bearing capacity of the spherical container is highest; under the same condition of volume, the spherical container has the minimal surface area; under the same conditions of pressure and material storage volume, spherical vessel save steel, and the area covered is the minimum. At present, spherical tank is mainly used to store all kinds of gas and liquefied gas, at home and abroad. Because spherical tanks is usually used to store flammable, explosive, toxic media, once the accident, it will cause huge loss to people’s lives and property, so the safety of use is very important.A variety of defects forms of spherical tank in diversity during using. But found in a comprehensive inspection, the most common form is crack defect. In view of the actual test case of 20 in-service spherical tank, a comprehensive analysis of the crack was found in the inspection process, and the crack type statistics and positions according to the cracks are summarized. The results show that, the crack occurs mainly in 2 parts, the first part is the part of pillar and the shell plate fillet weld; another part is the part of girth weld. And the two main parts of the cracks were analyzed, the analysis process is applied to the ANSYS finite element software for stress analysis. Finally, based on the analysis result put forward some preventive measures.We research the stress situation and stress distribution of the spherical tank.The purpose is to analyze the reason of crack, and put forward the corresponding prevention measures. The results of this paper provide reference for the use of units, inspection personnel needed in the production process and overall inspection of the key part, and the prevention of cracks provides guidance for prevention measures.